Thermal analysis of chemically synthesized polyaniline and effects of thermal aging on conductivity

Wei, Yen; Hsueh, Kesyin F.

doi:10.1002/pola.1989.080271312

Cited by 187 publications

(95 citation statements)

References 17 publications

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“…The two large shoulders in the thermal-degradation curves of all the samples, which correspond to degradation of the material in two steps, have been reported for other types of matrices such as polyaniline 27 and poly-(ethylene oxide). 28 In the case of polyaniline, 29,30 the degradation at lower temperature was attributed to evaporation of acid dopant, and the second transition was attributed to the degradation of the polymer backbone. The bimodal degradation of PLL and the lower PLL degradation temperature with clay loading observed in Figure 6 requires further investigation to identify specific degradation mechanisms, and work is now underway.…”

Section: Thermal Characterizationmentioning

confidence: 99%

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na⁺‐montmorillonite

Krikorian

Kurian

Galvin

et al. 2002

J Polym Sci B Polym Phys

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ABSTRACT:The feasibility of constructing polymer/clay nanocomposites with polypeptides as the matrix material is shown. Cationic poly-L-lysine ⅐ HBr (PLL) was reinforced by sodium montmorillonite clay. The PLL/clay nanocomposites were made via the solution-intercalation film-casting technique. X-ray diffraction and transmission electron microscopy data indicated that montmorillonite layers intercalated with PLL chains coexist with exfoliated layers over a wide range of relative PLL/clay compositions. Differential scanning calorimetry suggests that the presence of clay suppresses crystal formation in PLL relative to the neat polypeptide and slightly decreases the PLL melting temperature. Despite lower crystallinity, dynamic mechanical analysis revealed a significant increase in the storage modulus of PLL with an increase in clay loading producing storage modulus magnitudes on par with traditional engineering thermoplastics.

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Section: Thermal Characterizationmentioning

confidence: 99%

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na⁺‐montmorillonite

Krikorian

Kurian

Galvin

et al. 2002

J Polym Sci B Polym Phys

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“…were present in PANI [20,32]. ES (2) EB (1) ES ( ES (2) EB (1) ES ( Similar experiments were carried out using hydrochloric, phosphoric and trichloroacetic acids instead of sulfuric acid, as shown in figures 2(b)-(d), respectively.…”

Section: Doping Of Pani With Strong Acidsmentioning

confidence: 78%

Quartz crystal microbalance and spectroscopy measurements for acid doping in polyaniline films

Ayad

Zaki

2008

Science and Technology of Advanced Materials

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We investigated the doping of thin polyaniline (PANI) films, prepared by the chemical oxidation of aniline, with different acids. The initial step in the investigation is the preparation of PANI films from aqueous hydrochloric acid solution. This is followed by dedoping with ammonia to obtain a PANI base, which is subsequently doped with strong acids (e.g. hydrochloric, sulfuric, phosphoric and trichloroacetic acids) and with a weak acid (acetic acid). The dopant weight fraction (w), which is connected with the gain of mass during the doping of PANI, was determined in situ using a quartz crystal microbalance (QCM). The behavior of PANI upon doping with different anions derived from strong acids indicates that both proton and the anion uptake into the polymer chains occur sharply, rapidly, completely, and reversibly. However the uptake in the case in acetic acid is characterized by slow diffusion. The doping was studied at different concentrations of acetic acid. A second cycle of dedoping-redoping was also performed. The kinetics of the doping reaction is dominated by Fickian diffusion kinetics. The diffusion coefficients (D) of the dopant ions into the PANI chains were determined using the QCM and by UV-Vis absorption spectroscopy in the range of (0.076-1.64) × 10 −15 cm 2 s −1 . It was found that D in the second cycle of doping is larger than that evaluated from the first cycle of doping for high concentrations of acetic acid. D for the diffusion and for the dopant ion expulsion from the PANI chains was also determined during the redoping process. It was found that D for acetic acid ions in the doping process is larger than that calculated for the dedoping process.

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“…8, positive corona-doped films have much more stable conductivity over the temperature range studied, in comparison to polyaniline samples doped with the conventional HCl method. This may be attributed to the fact that HCl is a very volatile dopant for polyaniline, 19 being eliminated easily when the film is treated above room temperature. For the corona doped PANI on the other hand, the doping species appear either to be less volatile and/or interact more intensively with the PANI backbone.…”

Section: Resultsmentioning

confidence: 99%

Doping of Polyaniline by Corona Discharge

1997

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In the present article it is shown that a corona discharge can be employed to dope thin films of polyaniline ͑PANI͒ coated on poly͑ethylene terephthalate͒ films, allowing the electrical conductivity to be tuned within the range 10 Ϫ10 to 0.3 S cm Ϫ1. A study of the effect of different corona conditions, namely corona treatment for positive and negative polarities, air humidity, treatment time, corona current, and the geometry of the corona triode, on the electrical conductivity of the polyaniline is presented. The results indicate that the corona discharge leads to protonic doping of polyaniline similar to that which occurs in conventional protonic acid solution doping. Atomic force microscopic analysis shows that, as the PANI is exposed to the corona discharge, its globular morphology is disrupted leading to the appearance of droplet-like features and a significant decrease in the average height and surface roughness. Doping by corona discharge presents several advantages over the conventional solution method namely that it is a dry process which does not require use of chemicals reagents, and which is both rapid and avoids dopant migration. The latter can be important for applications of PANI in microelectronic devices.

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Thermal analysis of chemically synthesized polyaniline and effects of thermal aging on conductivity

Cited by 187 publications

References 17 publications

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na⁺‐montmorillonite

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na⁺‐montmorillonite

Quartz crystal microbalance and spectroscopy measurements for acid doping in polyaniline films

Doping of Polyaniline by Corona Discharge

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Thermal analysis of chemically synthesized polyaniline and effects of thermal aging on conductivity

Cited by 187 publications

References 17 publications

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na+‐montmorillonite

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na+‐montmorillonite

Quartz crystal microbalance and spectroscopy measurements for acid doping in polyaniline films

Doping of Polyaniline by Corona Discharge

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Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na⁺‐montmorillonite

Polypeptide‐based nanocomposite: Structure and properties of poly(L‐lysine)/Na⁺‐montmorillonite